Bags



Dec. 13, 1966 R. c.

Filed May 5, 1965 GOODWIN BAGS 8 SheetsSheet l M18/wif,

8 Sheets$heet 2 FIGBA.

BAGS

Dec. 13, 1966 R. c. GOODWIN Filed May 5, 196s A k a o H m l y .f w w wfLl D y 6. m mlliw J1 G. P .I.. F 5 W i A w 5 U l@ n UP 1| HHMU 4. iii ml# 7/ m. T\\`W\I\L F Dec. 13, 19,66 R. c. GOODWIN 3,291,376

BAGS

Filed May 5, 1965 8 Sheets-Sheet 6 2l a a Y x39@ i7 39a 23 57 FIG I9.

Dec. 13, 1966 R. c. GOODWIN 3,291,376

, BAGS Filed May 5, 1965 8 Sheets-Sheet '7 27 xi--CJl 29 99 /7 FIG. 2|.35h b 3\" 5 fx@ S R. C. GOODWIN BAGS a (35 s l/l/l l A' FIG. 24.

65 35d 5, Afa ,ff: r, i

FIG 25.

lI/I I l United States Patent O 3,291,376 BAGS Ralph C. Goodwin,Wayzata, Minn., assignor to Bemis Company, Inc., a corporation ofMissouri Filed May 5, 1965, Ser. No. 453,247 9 Claims. (Cl. 229-625)This invention relates to bags, and more particularly to bags made offlexible heat-scalable sheet plastic material such as polyethylene.

Among the several objects of this invention may be noted the provisionof improved plastic bags, and more particularly heavy-duty polyethylenebags for powdered or granular or like material, having end closuresadapted when the bags are filled to square off, Le., to assume arectangular form; the provision of bags such as described wherein theend closures are heat-sealed without any blocking thereof due to theheat-sealing; and the provision of a bag with such `an end closurehaving a valve for filling purposes. Other objects and features will bein part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated,

FIG. l is a view in elevation of a flat bag tube from which a bag ofthis invention is made with the ends of the tube opened up for theformation of diamond-fold bottom and top closures;

FIGS. 2 and 2A are views of opposite faces of a bottom closure insert;

FIGS. 3 and 3A are views of opposite faces of a top closure insert;

FIGS. 4 and 4A are views of opposite faces of a valve Hap;

FIG. 5 is a view similar to FIG. 1 showing the insert of FIGS. 2 and 2Aapplied to the bottom of FIG. l and the insert of FIGS. 3 and 3A and thevalve flap of FIGS. 4 and 4A applied to the top of FIG. 1, and furthershowing certain heat seals that are made;

FIGS. 6, 6A and 7 are enlarged sections taken on lines 6 6, 6A-6A and7-7 of FIG. 5, also showing how the heat seals may be made;

FIG. 8 is a view showing the completed bottom closure;

FIG. 9 is an enlarged section taken on line 9-9 of FIG. 8;

FIG. 9A is a view similar to FIG. 9 showing a modification;

FIGS. 10-12 are enlarged sections taken on lines Iii- 10, 11-11 and12-12 of FIG. 5;

FIG. 13 is a view showing the completed top closure;

FIG. 14 is an enlarged section taken on line lll-14 of FIG. 13;

FIG. l5 is a view similar to the lower half of FIG. l showing amodification of the bottom closure formation;

FIG. 16 is a view of the lower end of the tube used in making the FIG.modification;

FIG. 17 is an enlarged section taken on line 17-17 of FIG. 15;

FIG. 18 is a view similar to FIG. 2A showing a modification of the FIG.2A insert;

FIG. 19 is a view similar to FIG. 3A showing a modification ofthe FIG.3A insert;

FIG. 2O is a view similar to FIG. 4A showing a modification of the FIG.4A valve flap;

FIG. 2l is .a view similar to FIG. 9 but showing the use ofthe FIG. 18insert;

FIG. 22 is a view similar to FIG. 14 but showing the use of the FIG. 19insert and the FIG. 20 valve flap;

3,291,376 Patented Dec. 13, 1966 ICC FIG. 23 is a view similar to FIG. 5showing a modification in the method of manufacture; and

FIGS. 24 and 25 are enlarged sections taken on lines 24-24 and 25-25,respectively, of FIG. 23.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring to FIGS. 1, 5, 7-9 and 11-14 of the drawings, there isindicated at 1 a fiat bag tube from which a valve bag of this inventionmay be made, this tube being made of flexible heat-scalable sheetplastic material such as polyethylene. The opposed walls of the tube aredesignated 3 and 5. Wall 3 may be referred to as the front wall and wall5 as the back wall. The side folds of the tube, which constitute itsside edges, are designated 7 and 9. The tube has straight-cut ends. Itwill be understood that it may be segmented from a continuous length ofplastic tubing (e.g., polyethylene) of either the seamed or seamlesstype.

As shown in FIG. l, the tube 1 is provided with a diamond-fold bottomclosure formation by opening up the lower end of the tube and foldingback a lower end portion 11 of the front wall 3 on a fold line 13extending transversely across the tube. This operation results in theformation of end flaps 15 for the diamond-fold bottom closure and adownward extension 17 of the back Wall 5. Each of the end flaps 15 is oftriangular form, having an apex 19 at the respective end of fold line13, the sides of the triangle being constituted by folds 21 and 23 on 45lines extending from the apex. The inner edges of the triangular flaps15 are designated 25 and are spaced from one another a distance S asappears in FIG. 1.

Fold lines 27 and 29 are indicated in FIG. l extending across portions11 and 17. These fold lines are spaced equal distances on opposite sidesof line 13 and dene the width of the completed bottom closure. That partof portion 11 which lies outward of (above) line 27 constitutes a rstside flap 31 `of the bottom closure formation which is ultimately foldedover on line 27, and that part of portion 17 which lies outward of(below) line 29 constitutes a second side flap 33 of the bottom closurefor-mation which is ultimately folded over on line 29, as will appear.As illustrated, the fold lines 27 and 29 are located for lapping of theside flaps 31 and 33 when they are folded over.

Also as shown in FIG. 1, the tube is provided with a diamond-fold topclosure formation in the same manner as Vshown and describe-d for thebottom closure formation, the parts of the top closure formationcorresponding to those of the bottom closure formation being designatedby the same reference numerals as used for the parts of the bottomclosure formation with the letter a added.

Now referring to FIGS. 2 and 2A, there is illustrated a rectangularblank or insert of the same heat-scalable sheet plastic Imaterial (e.g.,polyethylene) as the material of the tube 1, which is used in formingthe bottom closure in a manner that will appear. This rectangular insert35 has an overall length L somewhat greaterV than the spacing S of theinner end edges 25 of the end flaps and a width W somewhat greater thanthe spacing of fold lines 27 and 29. It is provided on one face 37thereof (which face is its inside face as it is assembled with the tube)with stripes 39 (see FIG. 2A) of heatseal-inhibiting material at theends thereof, these stripes termin-ating short of the lengthwise edgesof the blank. The heat-seal-inhibiting material used at 39 `may be, forexample, a commercially available polyamide-base ink printed on theinsert. The spacing of the inner edges of stripes 39 -generally equalsS. The vother face 41 of the insert (FIG. `2) is bare (i.e., there is noheat-seal-inhibiting material thereon).

Referring to FIGS. 3 and 3A, there is illustrated a rectangular blank orinsert 45 of the same heat-sealable sheet plastic lmaterial (e.g.,polyethylene) as the material of the tube 1, which is used in formingthe top closure in a manner that will appear. This insert 45 has anoverall length L1 generally equal to S plus the distance D measuredalong a fold line 27a or 29a from the end of the fold line to the innerend edge of an end fla-p a. plus an overlap O, and has the same width Was insert 35. It is provided on one face 47 thereof (which face is onthe inside as the insert is assembled with the tube) with stripes 49 and51 of heat-seal-inhibiting material (FIG. 3A), one of these stripes (thestripe 51 as shown) being at one end of the insert and the other stripe49 being spaced therefrom the distance S. Stripes 49 and 51 terminateshort of the lengthwise edges of insert 45. The other face 53 of theinsert 45 (FIG. 3) is bare.

Referring to FIGS. 4 and 4A, there is illustrated a rectangular blank 55of heat-scalable sheet plastic material (e.g., polyethylene) preferablyof thinner gauge than the material of tube 1 and blank 45, which, aswill appear, provides a valve ap in the completed top closure. The valveap 55 hasa length L2 which is shorter than S plus O, and a width W. Itis provided on one face 57 thereof (which faces in as the valve flap isassembled with the tube) with a stripe 59 of heat-seal-inhibiting mate--rial (see FIG. 4A) at one end. This stripe terminates short of thelengthwise edges of the valve flap. The outer face 61 of the valve flap(FIG. 4) is bare. The inner and outer ends of valve ap 55 are designated55a and 55b.

As shown in FIG. 5, to complete the bottom closure, insert 35 ispositioned spanning 4the inner opposed ends of the triangular end flaps15 of the bottom closure formation with the striped ends of the insert35 inserted under the margins of the end flaps 15 with the bare face 41of the insert facing outward, an-d hence with the striped face 37 of theinsert facing inward (i.e., facing away from the margins of the endflaps 15). The lengthwise center line of the insert is generallyregistered with line 13 so that the insert extends generally equaldistances on opposite sides of line 13. Then, heat seals are made onlines 63 extending generally parallel to the inner -end edges of the endaps 15 and spaced slightly outward from edges 25 of end flaps 15 toeffect heat-sealing together ofthe end aps and the ends of the insert 35on intermediate portions of lines 63. Lines 63 extend out beyond thelateral edges of the insert 35 so that the end flaps 15 are heat-sealeddirectly to the underlying portions of the side flaps 31 and 33 on endportions of lines 63. The lines 63 extend endwise of the stripes 39 ofheat-sealinhibiting material so that -the intermediate portions of seals63 are made only between the end flaps 15 and the insert 35, leaving.the insert 35 free of the underlying regions of portions 11 and 17 ofthe walls of the tube. Also, heat seals are made on lines 65 extendingparallel to and somewhat inward of -the lateral edges of the insert 35and continuing over the end flaps 15. The heat seals at 65 seal togetherthe longitudinal margins of the insert 35 and the underlying regions ofportions 11 and 17 of the walls of the tube. Heat seals 65 are locatedslightly outward of fold lines 27 and 29.

In forming the heat seals 63 and 65, the bottom formation is positionedperpendicular to walls 3 and 5 of the tube, the walls being entered in aslot 67 in a table 69 (see FIGS. 6, 6A yand 7) and the bottom formationspread out flat on the table. Then the seals at 63 and 65 are made, forexample, by moving a platen 71 carrying hot sealing -bars or wires 73and 75 arranged in Ia pattern for making .the seals at 63 and 65downward to bring the hot bars or wires into pressure engagement withthe bottom formation. It will be apparent from FIG. 6 how theheat-seal-inhibiting material at 39 prevents sealing together of the endmargins of insert 35 and the underlying layer 17 of material.

After the formation of seals 63 and 65, the side flap 31 is folded overon fold line 27 to overlie the end flaps 15 and the side flap 33 isfolded over on fold line 29 to overlap the flap 31 as shown in FIGS. 8and 9. As appears in FIG. 9, this folding over of the side flaps iscarried lout around the edges of a thin flat heat-seal-inhibitingmandrel 77. This mandrel has a width corresponding to t-he width desiredfor t-he completed bottom closure (i.e., the spacing of lines 27 and 29)and is positioned extending endwise of the closure formation andcentered in respect thereto. After the side aps 31 and 33 have benfolded over and lapped, their lapping margins are heat-sealed togetheron two spaced lines of seal 79 extending across these margins. The seals79 are made, for example, by moving a platen 81 carrying hot sealingbars or wires 83 for making these seals downward to bring the wires intopressure engagement with the lapping margins of the side aps. Themandrel separates the side flaps 31 `and 33 from the insert 35 and theunderlying areas of portions 111 and 17 of the tube walls to prevent theheat seals made on lines 79 from striking through to the insert 35 andthese areas, thereby preventing blocking. The mandrel is then removed,and additional heat seals may be made along lines 84 extending parallelto and closely adjacent lines 63 to cause the side aps 31 and 33 tobecome sealed to the inner margins of the end flaps, the stripes 39 ofheatseal-inhibiting material preventing striking through of these seals84 to the underlying areas of portions 11 and 17 of the tube walls.

As appears in FIG. 9, when the side flaps 31 and 33 are folded over, thelateral margins 85 of the insert 35 fold up and over with the sideflaps. FIG. 9A shows a possible modification in which the lateralmargins of the insert 35 are folded down and under, instead of up andover and are heat-sealed Ialong lines 65b and 65C to portions 11 and 17of the front wall 3 and back wall 5, respectively. Heat-seal-inhibitingmaterial is provided on face 37 along lateral margins 85 of insert 35 toinllibit sealing of these lateral margins to the insert body when seals65 are made. In FIG. 9A, the mandrel 77 of FIG. 9 has been removed frombetween the foldedoverside flaps 31 and 33 and 4the insert 35.

As shown in FIGS. 5 and 10, to complete the top closure (and to provideit with a valve), the valve ap 55 is positioned with its striped end 55bunderlying the inner margin of one of the top closure end flaps 15a (theleft-hand end flap 15a las Shown), with the barc face 61 of the valve apengaging the inside face of the end flap yand the stripe 59 ofheat-seal-inhibiti-ng material facing inward. The insert 45 ispositioned with its end having stripe 51 thereon underlying the othertop closure end flap 15a (the right-hand end ap 15a as shown), with theinsert 45 extending over the leftlhand top closure end ap 15a, and withstripes 49 and 51 facing inward. Stripe 49 overlies the inner margin ofthe left-hand end ap. Both valve flap 55 and insert 45 are centered inrespect to fold line 13a of the top closure formation.

Then, heat seals are made on lines 63a extending generally parallel tothe inner end edges 25a of the top closure end flaps 15a spaced slightlyoutward from edges 25a to effect sealing together of the inner margin ofthe right-hand end flap 15a land the right-hand end of the insert 45 onthe right-hand line 63a, and to effect sealing together of the innermargin of the left-hand end tap 15a and the left-hand end of valve flap55 on the left-hand line 63a. Lines 63a (like lines 63) extend outbeyond the lateral edges of the insert 45 (and valve ap 55) so that theend flaps 15a are heat-sealed directly to the underlying portions of theside flaps 31a and 33a of the top closure formation on end portions oflines 63a. The lines 63a extend endwise of stripes 49 and 51 ofheat-seal-inhibiting material on insert 45, and lthe leftliand line 63aextends endwise of the stripe 59 of heatseal-inhibiting material onvalve flap 55. Accordingly,

e the intermediate portion of the right-hand seal 63a is made onlybetween right-hand end flap |15a and the insert 54, sealing of theright-hand end of the insert 45 to the underlying layer of materialbeing prevented by stripe 51 (see FIG. 10). Stripe 49 prevents sealingof insert 45 along the left-hand line 63a to the left-hand end flap 15ato leave Ian opening 87 for entry of a till-ing spout underneath `theleft-hand end portion of the insert 45, `sealing of the lrigh.thand endof the insert 45 of valve flap 55 to the underlying layer of material.Also, heat seals `are made on lines 65a (corresponding to lines 65)extending parallel lto `and :slightly inward of the lateral edges ofinsert 45 Iand valve Hap 55 and continuing over the end flaps 15a. Theheat `seals at 65a seal together the lateral margins of the insert 45:and valve flap 55 and the underlying regions of .portions 11a tand 17aof the walls of the .tube 1, and lare located `slightly outward of foldlines 27a and 29a of the top closure formation.

In formi-ng the heat :seals 63a and 65a, the top closure Aformation ispositioned perpendicular to Wall-s 3 .and 5 of the tube, and entered `inslot 67 of ta-ble 69, 4and the sea-ls `are made in the same manner asabove described in connection with seals 63 and `65.

After the forming of seals 63a and 65a, the side flap 31a of the topclosure formation is folded over on fold line 27a to overlie the endflaps 15a `and the side flap 33a is folded over on fold line 29a tooverlap the flap 31a as shown in FIG. 13 and 14. As appears in FIG. 14,this folding over of the side flaps 31a and 33a is carried out aroundthe edges of heat-seal-inhibiting mandrel 77 (as above described)applied on top of the insert 45. After the side aps 31a and 33a havebeen folded over and Ilapped, their lapping margins are heat-sealedtogether on lines 79a (corresponding to lines 79) inthe same manner asabove described in connection with lines 79. The mandrel separates theside flaps 31a and 33a from the insert 45 and valve flap 55 and the`underlying areas of portions 11a and 17a -on the ltube walls to preventthe seals made on lines 79a from striking through to these areas,thereby pre-venting blocking. The mandlrel is then removed, and heatseals may Ibe rnade along lines 84a (corresponding to lines 84) to causethe side flaps 31a yand 33a to become seatled adjacent their right endsto the right-hand end flap 15a, and to cause the `side flaps 31a and 33ato become sealed adjacent their left ends to insert 45, -blocking beingprevented by stripes 49 and 51.

FIGS. 15417 illustrate a modification of the bottom closure describedabove, which is similar to the latter, except that the insert .for thebottom closure, which is designated 35a to distinguish it from theinsert 35, is positioned spanning the inner lopposed ends of thetriangular end flaps 15 with the ends of the insert overlying (insteadof underlying) the inner end' margins of the end aps 15. In thismodication, the insert 35a does not have any heat-sea-inhibitingmaterial, and the tube 1 is preliminarily prepared with stripes 39a ofheat-seal-inhibiti-n g material on the inside at the cornersV thereof,these strips 39a serving the same purpose as :stripes 39 of insert 35.

FIG. 18 shows a modified version 35h of the insert 35 adapted forforming the bottom closure without the use of the mandrel 77. Insert 35his essentially identical to insert 35 with the addition of a broadlongitudinal central stripe 99 of heat-seal-inhibiting material on theface 37 of the insert. This makes the pattern of heat-seal-inhibitingmaterial on face 37 in the .form `of an H. This same stripe 99 may beused on the insert 35a of FIG. 15.

FIG. 19 shows a modified version 45a of the insert 45 and FIG. 20 showsa modified version 55a of the valve flap 55 adapted for forming the topiolosure Without the use of the mandrel 77. Insert 45a is essentiallyidentical to insert 45 with the addition of a broad longitudinal centralstripe 101 of heat-seal-inhibiting material extending between stripes 49and 51 on the face 47 of the insert,

making Ithe pattern of heat-seal-inhibiting materral on face 47 in theform Iof an H. Valve Hap 55a is essentially identical to insert 45 withthe addition lof `a .broad longitudinall central stripe 103 ofheat-seal-inhibiting material on face 57 of the valve flap, making thepattern of heatseal-inhibiting material on .face 5'7 in the form of a T.

FIG. 2l shows how the stripe 99, while allowing beatsealing together at79 of the lapping margins of side flaps 31 and 33 of the bottom closureand the insert 35b, as may be desirable, prevents striking through ofseals 79 to portions 11 :and 17 of the Walls of the tube, thereby toprevent blocking.

FIG. 22 shows how the stripe 101 on insert 45a of the top closure, whileallowing heat-sealing together at 79 of the lapping margins of the sideaps 31a and 33a of the top closure and the insert 45a, as may bedesirable, prevents striking through lof seals 79 to the valve ap 55a,and further shows how stripe 103 on valve flap 55a, prevents sealingtogether of the valve flap and portions 11a and 17a of the walls of thetube on lines 79, thereby to prevent blocking.

FIGS. 23-25 show a modification of the method of forming a closure atone end of the tube 1 in which inhibition of heat-sealing to preventblocking of the closure is edected by means of a heat-seal-inhibitingmandrel rather than by providing heat-seal-inhibiting material on theinsert or on the tube. FIG. 23 shows the lower end of the tube opened upin Ithe same manner as shown in FIGS. 1 and 5 and having an insert 35aapplied thereto in the same manner as insert 35 is applied in FIG. 5.Insert 35a is the same yas insert 35 except that it has noheat-seal-inhibiting material thereon. As shown in FIG. 23, seals aremade on lines 63 and 65, the same as in FIG. 5, but, before making theseseals, a heat-seal-inhibiting mandrel 111 is positioned underneath theinsert (see particularly FIGS. 24 and 25) to prevent striking through ofthe heat-sealing on the intermediate portions of seals 613 so that theintermediate portions of these seals are made only between the end aps15 and the insert 35a, leaving the insert free Vof the underlyingregions of portions 11 and 17 of the walls of the tube. Noteparticularly from FIGS. 23 and 24 how the end portions fof the mandrel111 :are interposed between the end margins of insert 35a and theunderlying layer 17 of material to prevent seals 63 from strikingthrough to llayer 17 in the regions of seals 63 between lines 27 and 29.For this purpose, mandrel 111 is of rectangular form, having a lengthsufficiently greater than the spacing of the inner opposed edges 25 ofthe end flaps 15 to extend beyond t-he locations of the lines of seal63, and a Width approximating the spacing of fold lines 27 and 29. Themandrel is positioned in centered relation with respect to the closureformation so that its ends lie under the ends o-f the insert and its.lengthwise edges lilla lie along the locations 4of fold lines 27 and 29to lie inward of the lines of seal 65 and to permit the folding over ofside flaps 31 and 33 around the lengthwise edges of the mandrel. Theclosure is completed in the same manner as previously described inconnection with FIGS. 8 and 9, using mandrel 77, leaving mandrel 111 inplace until the seals 79 and 84 have been made.

The method shown in FIGS. 23-25 may be used for forming a bottom closureonly, in which case the mandrel 111 is removed through the open upperend of the tube. It may :also be used in forming both a bottom closureand valved top closure, in which case the mandrel 111 used for formingthe bottom lclosures may be removed before the valved top closure isformed, and the mandrel used in forming the valved top closure Imay beremoved through the valve.

It will be understood that each of the mandrels 77 and 111 may consist,for example, of a thin sheet metal plate coated with any conventionalheat-seal-inhibiting material, such as a polymerized tetrauoroethylenesold under the trade name Teflon by E. I. du Pont de Nemours & Co., or asheet of Teon per se, or the like.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A bag formed from a flat tube of heat-sealable sheet material, saidtube having a closure formation at one end comprising inwardly directedend iiaps and rst and second side flaps, and an insert of heat-scalablesheet material extending between the end aps and having its outer endmargins lapping the inner end margins of said end aps, said insert beingheat-sealed at least at one end margin thereof to the inner end marginof the respective end ap at one end of said closure formation, said sideflaps being folded over to overlie the end flaps and said insert, andbeing heat-sealed together, said bag having a coating ofheat-seal-inhibiting material on the inside of the inner of said lappingmargins at said one end of said closure formation where said one endmargin of the insert is heat-sealed to the inner end margin of saidrespective iiap to inhibit blocking of said closure formation along thisheat seal.

2. A bag as set forth in claim 1 wherein said insert is also heat-sealedat its other end margin to the inner end margin of the other end flap atthe other end of said closure formation, and said bag has a coating ofheatseal-inhibiting material on lthe inside of the inner of lsaidlapping margins at said other end of said closure formation where saidother end margin of the insert is heatsealed to the inner end margin ofsaid other end flap to inhibit blocking of said closure formation alongthe latter heat seal.

3. A bag formed from a flat tube of heat-scalable sheet material, saidtube having a closure formation at one end comprising inwardly directedend flaps and iirst and second side aps, and an insert of heat-scalablesheet material extending between the end flaps and lapping the latter,said insert being heat-sealed at one end thereof to the inner end marginof one of the end flaps, said side flaps being folded over to overliethe end iiaps and said insert, and being heat-sealed together, andheat-seal-inhibiting material provided in the region where said one endof the insert is heat-sealed to the inner end margin of said one endflap to inhibit blocking of said closure formation along this heat seal,said insert also being heatsealed at its other end to the inner endmargin of the other end flap, heat-seal-inhibiting material beingprovided in the region where said other end of the insert is heatsealedto the inner end margin of said other end flap to inhibit blocking ofsaid closure formation along the latter heat seal, the ends of theinsert lying under the margins of the end flaps, and saidheat-seal-inhibiting material being applied to said ends of the inserton its inside face.

4. A bag as set forth in claim 3 wherein the side aps overlap and are-heat-sealed together along their overlap, and wherein said insert isprovided with heat-seal-inhibiting material on its inside face in theregion of the heatsealing of the side aps along their overlap.

5. A bag formed from a flat tube of heat-sealable sheet material, saidtube having a closure formation at one end comprising inwardly directedend aps and first and second side aps, and an insert of heat-sealablesheet material extending between the end flaps and lapping the latter,said insert being heat-sealed at one end thereof to the inner end marginof one of the end flaps, said side fiaps being folded over to overliethe end aps and said insert, and being heat-sealed together, andheat-seal-inhibiting material provided in the region where said one endof the insert is heat-sealed to the inner end margin of said one endiiap to inhibit blocking of said closure formation along this heat seal,said insert also being heatsealed at its other end to the inner endmargin of the other end iiap, heat-seal-inhibiting material beingprovided in the region where said other end of the insert is heat-sealedto the inner end margin of said other end iiap to inhibit blocking ofsaid closure formation along the -latter heat seal, the ends of theinsert lying over the margins of the end aps, and saidheat-seal-inhibiting material being applied to the inside faces of theend flaps extending along their inner margins.

6. A 'bag formed from a flat tube of heat-scalable sheet material, saidtube having a closure formation at one end comprising inwardly directedend aps and first and second side flaps, and an insert -of heat-sealablesheet material extending between the end flaps and lapping the latter,said insert being heat-sealed at one end thereof to the inner end marginof one of the end flaps, said side aps being folded over to overlie theend flaps and said insert, and being heat-sealed together, andheat-sealinhibiting material provided in the region where said one endof the insert is heat-sealed to the inner end margin of said -one endiiap to inhibit blocking of said closure formation along this heat seal,the insert extending over the other end flap and being free of thelatter to provide a valve opening for entry of a lilling spout betweenthe insert and said other end flap, the side iiaps overlapping and beingheat-sealed together along their overlap, and the said one end Iof theinert lying under the inner end margin Vof said one end flap, saidheat-seal-inhibiting material being applied to the insert on its innerface.

7. A bag formed from a at tube of heat-sealable sheet material, saidtube having a closure formation at one end comprising inwardly directedend flaps and first and second side flaps, and an insert ofheat-scalable sheet material extending between the end flaps and lappingthe latter, said insert being heat-sealed at one end thereof to theinner end margin of one of the end flaps, said side flaps lbeing foldedover to overlie the end aps and said insert, and being heat-sealedtogether, and heat-sealinhibiting material provided in the region wheresaid one end of the insert is heat-sealed to the inner end margin ofsaid one end Hap to inhibit blocking of said closure formation alongthis heat seal, the insert extending over the other end iiap and beingfree of the latter to provide a valve opening for entry of a fillingspout between the insert and said other end Hap, a valve ap heat-sealedto the inside of the inner margin of the said other end iiap andextending inward therefrom, the side aps overlapping and beingheat-sealed together along their overlap, and said insert and said valveflap each being provided With heat-seal-inhibiting material on theinside faces thereof in the region of the heat-sealing of the side apsalong their overlap.

8. A bag formed from a flat tube of heat-sealable sheet material, saidtube having a closure formation at one end comprising inwardly directedend flaps and first and second side flaps, a valve flap afheat-seala'ble sheet material extending inward from one of said endflaps, said valve flap having its outer end margin lapping the inner endmargin of said one end flap on the inside of the latter and beingheat-sealed thereto, and an insert of heatsealable sheet materialextending between the end flaps and lapping the latter, said insertextending on the outside of said one end ap and having its side marginsheatsealed to said one end flap but otherwise being free of said one endflap to provide a valve opening for entry of a filling spout between theinsert and said valve ap, and said insert having its other endheat-sealed to the inner end margin of the other end ap, said side flapsbeing folded over to overlie the end liaps and said insert, and beingheat-sealed together.

9. A bag formed from a at tube of heat-scalable sheet material, saidtube having a closure formation at one end comprising inwardly directedend aps and first and second side flaps, a valve flap of heat-scalablesheet material extending inward from one of said end iiaps, said ValveHap having its outer end margin lapping the inner end margin of said oneend flap and being heat-sealed thereto, and an insert of heat-sea-lablesheet material extending between the end flaps and overlying the valveflap and said one end ilap, said insert having its side marginsheat-sealed to said one end flap but otherwise being free of said oneend flap to provide a valve opening for entry of a lling spout betweenthe insert and said valve ap, said insert having its other end marginheat-sealed to the inner end margin -of the other end flap, said baghaving heat-seal-inhibiting material in the region Where the valve ilapis heat-sealed to the inner end margin of said -one end flap to inhibitblocking of the closure formation and said valve opening along this heatseal, said bag also having heat-seal-inhibiting materia-l in the regionWhere the insert is heat-sealed to the inner end margin of said otherend flap to inhibit blocking of the closure formation along this heatseal.

References Cited by the Examiner JOSEPH R. LECLAIR, Primary Examiner.

DAVID M. BOCKENEK, Examiner.

1. A BAG FORMED FROM A FLAT TUBE OF HEAT-SEALABLE SHEET MATERIAL, SAIDTUBE HAVING A CLOSURE FORMATION AT ONE END COMPRISING INWARDLY DIRECTEDEND FLAPS AND FIRST AND SECOND SIDE FLAPS, AND AN INSERT OFHEAT-SEALABLE SHEET MATERIAL EXTENDING BETWEEN THE END FLAPS AND HAVINGITS OUTER END MARGINS LAPPING THE INNER END MARGINS OF SAID END FLAPS,SAID INSERT BEING HEAT-SEALED AT LEASAT AT ONE END MARGIN THEREOF TO THEINNER END MARGIN OF THE RESPECTIVE END FLAP AT ONE END OF SAID CLOSUREFORMATION, SAID SIDE FLAPS BEING FOLDED OVER TO OVERLIE THE END FLAPSAND SAID INSERT, AND BEING HEAT-SEALED TOGETHER, SAID BAG HAVING ACOATING OF HEAT-SEAL-INHIBITING MATERIAL ON THE INSIDE OF THE INNER OFSAID LAPPING MARGINS AT SAID ONE END OF SAID CLOSURE FORMATION WHERESAID ONE END MARGIN OF THE INSERT IS HEAT-SEALED TO THE INNER END MARGINOF SAID RESPECTIVE FLAP TO INHIBIT BLOCKING OF SAID CLOSURE FORMATIONALONG THIS HEAT SEAL.